JPH0730305U - Engine cam refueling device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] An engine cam oil supply device that allows a thick oil film to be formed over a wide range of the sliding contact surface while efficiently ejecting lubricating oil to reduce the oil pump discharge loss. I will provide a. A lubricating oil passage 17 is provided at an axial center portion of a cam shaft 16 in which a cam 15 for operating an intake valve or an exhaust valve is formed.
To form. A bearing oil supply hole 20 is formed in the bearing portion 16 a of the camshaft 16 to guide the lubricating oil in the lubricating oil passage 17 to the inner peripheral surface of the bearing 18. Lubricating the inner peripheral surface of the bearing 18 to receive the lubricating oil led to the bearing oil supply hole 20 and eject the lubricating oil toward the contact surface between the cam 15 and the tappet (valve driving member) 3 that contacts the cam 15. The oil groove 21 is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cam oil supply device for an engine that supplies lubricating oil to a contact surface between a cam in an engine and a valve drive member such as a tappet or rocker arm that operates an intake valve or an exhaust valve by the rotation of the cam. Is.

[0002]

[Prior art]

 Generally, an engine uses a cam as a driving means of a valve mechanism for opening and closing intake and exhaust valves. Therefore, it is necessary to lubricate the contact surface between this cam and the valve driving member of the intake / exhaust valve (see Japanese Utility Model Laid-Open No. 61-53507).

Therefore, as shown in FIG. 8, in a DOHC (double overhead camshaft) engine having a structure in which the cam surface 1a of the cam 1 is in direct sliding contact with the tapette 3 as a valve driving member, the DOHC (double overhead camshaft) engine is smooth for a long time. In order to obtain the sliding contact operation, it is necessary to supply the lubricating oil between the cam 1 and the tappet 3. In this cam oil supply mechanism, the hollow portion of the shaft center of the cam shaft 4 in which the cam 1 is integrally formed is used as the lubricating oil passage 5, and the cam 1 is provided with a radial oil supply hole 6 to form a radial direction. When the oil supply hole 6 faces downward due to the rotation in the direction of arrow R, the lubricating oil in the lubricating oil passage 5 is guided between the outer peripheral surface of the cam 1 and the tappet 3 through the oil supply hole 6.

In FIG. 8, an intake valve 12 and an exhaust valve 13 are provided in the intake passage 10 and the exhaust passage 11, respectively, and the intake valve 12 and the exhaust valve 13 are closed by valve springs 14 in a closing direction. Being energized.

Further, in the DOHC engine of FIG. 9, a refueling pipe 8 is provided between both ends of the cam bearing bracket 7, and a refueling pipe 9 is provided with an arrow from a refueling hole 9 formed at a position above each cam 1 in the refueling pipe 8. As shown, the lubricating oil is dripped onto the cam 1, and the dripped lubricating oil is supplied between the cam 1 and the tappet 3 as the cam 1 rotates.

Further, as shown in FIG. 10, in the DOHC engine having a structure in which the cam surface 1 a of the cam 1 is in sliding contact with the rocker arm 2 as a valve driving member, lubricating oil is supplied between the cam 1 and the rocker arm 2. There is a need to. As the cam oil supply mechanism, a hollow portion of the shaft center of the non-rotating rocker shaft 30 is used as a lubricating oil passage 31, and an oil supply hole 32 penetrating the rocker shaft 30 and the rocker arm 2 is provided, and the lubricating oil is supplied from this oil supply hole 32. Was ejected toward the cam 1.

[0007]

[Problems to be solved by the device]

 However, in the cam refueling mechanism shown in FIG. 8, it is necessary to make the diameter of the refueling hole 6 sufficiently smaller than the width of the cam 1 (width in the front-back direction in the drawing) so as not to impair the strength of the cam 1. When the cam 1 rotates at a high speed, an oil film is formed only on the central portion of the sliding contact surface between the cam 1 and the tappet 3, and the amount of lubricating oil supplied to both sides of the sliding contact surface is insufficient. Further, when the cam surface 1a comes into sliding contact with the tappet 3, a high pressure is applied to the cam surface 1a by compressing the valve spring 14, and therefore when the oil supply hole 6 is bored in the cam surface 1a, the sliding contact with the tappet 3 is made. As a result, the cam surface 1a may be damaged. Therefore, the oil supply hole 6 must be drilled in the semicircular base portion 1b of the cam 1.

Further, the lubricating oil flows out from the oil supply hole 6 during a period of about 1/2 rotation of the cam 1 in which the oil supply hole 6 faces downward with respect to the horizontal direction. Since it is provided in the base portion 1b, only a part of the lubricating oil that has flown out when the oil supply hole 6 approaches the tapette 3 is effectively used. As a result, the oil pump discharge loss increases despite the lack of lubricating oil for forming an oil film on the sliding contact surface.

On the other hand, in the cam oil supply mechanism shown in FIG. 9, the lubricating oil dropped on the upper portion of the cam 1 is scattered by the centrifugal force as the cam 1 rotates, and a thick oil film cannot be formed. Nevertheless, since the lubricating oil is constantly dripping, the lubricating oil discharge loss from the oil pump also increases.

Further, in the cam oil supply mechanism shown in FIG. 10, the vertical swing of the rocker arm 2 causes the lubricating oil to be scattered upward as indicated by arrows P10 and P20. During high-speed operation in which the swing speed of the arm 2 is fast, the amount of lubricating oil adhering to the cam portion 1a decreases. Further, when the lubricating oil is supplied to the cam portion 1a from the position of the intake valve 12 side, that is, the rocker arm 2 on the right side, the cam 1 hits the rocker arm 2 by rotating 1/2 times from that position. Is scattered by the centrifugal force of the cam 1, so that the amount of lubricating oil adhering to the cam portion 1a is further reduced. However, since the lubricating oil passage 31 is provided at the center of the rocker shaft 30 and the oil supply hole 32 that penetrates the rocker shaft 30 and the rocker arm 2 is provided, the number of processing steps for the rocker shaft 30 and the rocker arm 2 is increased. To do.

In view of this, the present invention efficiently supplies the lubricating oil so as to reduce the discharge loss of the oil pump, but can sufficiently supply the lubricating oil so that a thick oil film can be effectively formed over a wide range of the sliding contact surface. The purpose is to provide an engine cam refueling device.

[0012]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a cam for operating an exhaust valve or an intake valve, a cam shaft provided with this cam, and a lubricating oil passage formed in an axial center portion, and a bearing of this cam shaft. And a cam for receiving the lubricating oil thus formed and a bearing oil supply hole formed on the inner peripheral surface of the bearing for discharging the lubricating oil of the lubricating oil passage to the inner peripheral surface of the bearing. A lubricating oil groove for ejecting lubricating oil toward the contact surface with the valve drive member that contacts the cam is provided.

[0013]

[Action]

 During one rotation of the cam, during the period when the bearing oil supply hole does not face the lubricating oil groove, the bearing oil supply hole is blocked by the inner peripheral surface of the bearing, and the lubricating oil in the lubricating oil passage does not come out. . Then, the lubricating oil in the lubricating oil passage flows into the lubricating oil groove through the bearing oiling hole only during the period when the bearing oiling hole faces the lubricating oil groove, and this inflowing lubricating oil flows from the lubricating oil groove to the cam. It is ejected toward the contact surface with the valve drive member that contacts the cam. As described above, the bearing oil supply hole is opposed to the lubricating oil groove during one rotation of the cam, the lubricating oil is intensively ejected only for a certain period, and the lubricating oil is efficiently supplied toward the contact surface. The discharge loss of the pump can be significantly reduced, and a thick oil film can be formed over a wide range of the sliding contact surface between the cam and the valve drive member while the amount of lubricating oil is small.

[0014]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a vertical sectional view showing a half portion of an embodiment of the present invention, FIG. 2 is a partially cutaway plan view of a main portion, and FIG. 3 is an enlarged vertical sectional view of the main portion. 8 which are the same as or equivalent to those in FIG. 8 are designated by the same reference numerals. Similar to the case of FIG. 8, this embodiment shows a case where it is applied to a DOHC engine having a structure using the tappet 3 as a valve driving member. However, the rotation direction R of the camshaft 16 is opposite to the case of FIG.

As shown in FIG. 1, a lubricating oil passage 17 is formed in a hollow central portion of a cam shaft 16 whose both ends are rotatably supported by bearings (not shown). As shown in FIG. 2, the cam shaft 16 is integrally formed with a pair of cams 15 at predetermined intervals in the axial direction, and a bearing portion 16a is integrally formed between the cams 15 and 15. Has been done. As shown in FIG. 3, the bearing portion 16a is rotatably held by a bearing 18 in which a lower bearing portion 18a and an upper bearing portion 18b are fixed by bolts 19.

A bearing oil supply hole 20 is formed in the radial direction in the bearing portion 16a of the camshaft 16, and when the bearing oil supply hole 20 faces downward as the camshaft 16 rotates, the lubricating oil The lubricating oil in the passage 17 flows toward the inner peripheral surface of the bearing 18 through the bearing oil supply hole 20.

On the other hand, on the inner peripheral surface of the lower bearing portion 18a of the bearing 18, as shown in detail in FIG. 3, a lubricating oil groove 21 extending from a position near the upper surface to the bottom is provided. The lubricating oil groove 21 is a lubricating oil introducing groove portion 21a extending from a portion near the upper surface to a bottom portion with a curvature along the inner peripheral surface of the lower bearing portion 18a, and communicates with the lubricating oil introducing groove portion 21a as shown in FIG. As shown by an arrow P, the tappet 3 and the cam 15 on both sides are formed with a pair of lubricating oil ejection groove portions 21b extending obliquely downward toward the sliding contact portion.

The cam oil supply device of the above-described embodiment operates as follows. That is, as shown in FIG. 3, the bearing oil supply hole 20 is located at a position corresponding to the ramp portion 15c at an intermediate position between the substantially semicircular base portion 15b of the cam 15 and the cam surface 15a as seen in the axial direction. When the bearing oil supply hole 20 faces the upper end portion of the lubricating oil groove 21a of the lubricating oil groove 21 as the cam 15 rotates in the direction of arrow R, the lubricating oil in the lubricating oil passage 17 is formed. Starts to flow into the lubricating oil introducing groove 21a of the bearing 18 through the shaft oil receiving hole 20, and the amount of this inflow increases further as the cam 15 rotates. Immediately before the ramp portion 15c comes into contact with the tapette 3, the lubricating oil filled in the lubricating oil introduction groove portion 21a reaches the contact surface between the tappet 3 and the cam 15 on both sides from each lubricating oil introduction groove portion 21b. It is ejected toward the arrow P direction.

Therefore, since the lubricating oil is intensively ejected at the most preferable timing just before the contact of the ramp portion 15c of the cam 15 with the tappet 3 is started, the mutual contact surface between the cam 15 and the tappet 3 is wide. A thick oil film can be efficiently formed over the range.

Further, during one rotation of the cam 15, the bearing oil supply hole 20 is blocked by the inner peripheral surface of the bearing 18 while the bearing oil supply hole 20 does not face the lubricating oil introduction groove portion 21 a of the lubricating oil groove 21. Therefore, the lubricating oil in the lubricating oil passage 17 is not discharged, and the lubricating oil is intensively ejected only for a certain period of time in which the bearing oil supply hole 20 faces the lubricating oil groove 21. It can be reduced significantly. Moreover, there is an advantage that oil can be supplied to the bearing portion 16a itself, that is, between the outer peripheral surface of the bearing portion 16a and the inner peripheral surface of the bearing 18.

Furthermore, since the cam oil supply device described above has a configuration in which the lubricating oil groove 21 is formed in the bearing 18, it can be molded by casting and can be manufactured at low cost. Further, since the bearing oil supply hole 20 is formed in the bearing portion 16a of the camshaft 16 that does not slide contact with the tappet 3, there is no influence such as damage due to the sliding contact with the tappet 3, so that this bearing oil supply hole 20 is not The bearing portion 15a can be formed at any position corresponding to the cam surface 15a, the base portion 15b and the ramp portion 15c, and the degree of freedom in design is high.

FIG. 4 shows another embodiment of the present invention. In FIG. 4, a pair of lubricating oil grooves 21 and 21 are provided on the left and right when viewed from the axial direction of the camshaft 16, and communication between them is blocked by a weir 35. As shown in FIG. 5, the camshaft 16 rotates in the direction R opposite to that in FIG. Immediately before the contact of the ramp portion 15c of the cam 15 with the tappet 3 starts, when the bearing oil supply hole 20 faces the left lubricating oil groove 21, the lubricating oil flows from the lubricating oil discharge groove portion 21b to the tappet 3 as shown by an arrow P1. 3 is supplied to the left half of the upper surface of the tappet 3 that forms a sliding contact surface between the cam 3 and the cam 15, and then, as shown in FIG. 6, when the bearing oil supply hole 20 faces the lubricating oil groove 21 on the right side, lubrication is performed. Oil is supplied to the right half of the tappet 3 from the lubricating oil lead-out groove portion 21b as shown by an arrow P2. As a result, the lubricating oil is directly supplied over a wider area on the upper surface of the tappet 3, and a thick oil film is formed.

On the other hand, also in the engine having the structure in which the rocker arm 2 shown in FIG. 10 is used as the valve driving member, the cam shaft 16 and the bearing 18 having the same configuration as in FIG. 3 can be used. An example thereof is shown in FIG. In FIG. 7, an introduction hole 37 is formed in the rocker arm 2 so as to face the cam 15 in the radial direction, and is supplied to the upper surface of the rocker arm 2 from the bearing oil supply hole 20 of the cam shaft 16 through the lubricating oil groove 21. A part of the lubricating oil and a part of the lubricating oil scattered around are picked up by the introduction hole 37, and are supported by the rocker arm 2, that is, the inner peripheral surface of the rocker arm 2 and the rocker shaft 30. It is supplied between the outer peripheral surface. This also lubricates the support portion of the rocker arm 2. Further, since it is not necessary to provide the rocker shaft 30 with a lubricating oil passage or an oil supply hole (see 31 and 32 in FIG. 10) at the center of the rocker shaft 30, the number of processing steps is reduced.

In the embodiment shown in FIG. 7, a lubricating oil groove 21 provided in the bearing 18 may be additionally provided with an ejection groove portion for ejecting lubricating oil toward the introduction hole 37. A large amount of lubricating oil can be reliably introduced into the entry hole 37.

In each of the above embodiments, the bearing 18 is formed with the lubricating oil groove 21 having the pair of lubricating oil jetting groove portions 21b toward the cams 15 on both sides, but the cam 15 is provided only on one side of the bearing 18. In this case, the lubricating oil groove 21 having only one lubricating oil ejection groove portion 21b is formed.

[0026]

[Effect of device]

 As described above, according to the engine cam lubrication device of the present invention, the lubricating oil in the lubricating oil passage is lubricated only in the period in which the bearing lubrication hole formed in the bearing portion of the camshaft faces the lubricating oil groove of the bearing. Since it is made to flow into the lubricating oil groove through the nozzle and is jetted between the cam and the valve drive member, the lubricating oil is jetted intensively and efficiently only for a certain period during one rotation of the cam, and It is possible to effectively form a thick oil film over a wide range of the sliding contact surface of the valve drive member. Also, in the period when the bearing oil supply hole does not face the lubricating oil groove of the bearing, the bearing oil supply hole is blocked by the inner peripheral surface of the bearing and the lubricating oil cannot be drawn out, so the discharge loss of the oil pump is significantly reduced. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a half portion of an engine to which an embodiment of the present invention is applied.

FIG. 2 is a partially cutaway plan view showing an essential part of the embodiment.

FIG. 3 is an enlarged vertical sectional view showing a main part of the embodiment.

FIG. 4 is a partially cutaway plan view showing an essential part of another embodiment of the present invention.

FIG. 5 is an enlarged vertical sectional view showing a main part of the embodiment.

FIG. 6 is an enlarged vertical cross-sectional view of the main parts showing the operation of the embodiment.

FIG. 7 is a vertical sectional view showing a half portion of an engine to which another embodiment of the present invention is applied.

FIG. 8 is a longitudinal section of an engine including a conventional cam oil supply device.

FIG. 9 is a longitudinal section of an engine provided with another conventional cam oil supply device.

FIG. 10 is a longitudinal section of an engine provided with still another conventional cam oil supply device.

[Explanation of symbols]

2 ... Rocker arm (valve drive member), 3 ... Tappet (valve drive member), 12 ... Intake valve, 13 ... Exhaust valve, 15 ... Cam, 16 ... Cam shaft, 16a ... Bearing part, 17 ... Lubricating oil passage, 18 ... bearing, 20 ... bearing oil supply hole, 21 ... lubricating oil groove.

Claims (1)

[Scope of utility model registration request] 1. A cam for operating an exhaust valve or an intake valve, a cam shaft provided with this cam and having a lubricating oil passage formed in an axial center thereof, and a bearing portion of this cam shaft, wherein said lubricating is provided. A bearing oil supply hole for guiding the lubricating oil of the oil passage to the inner peripheral surface of the bearing, and a valve driving member formed on the inner peripheral surface of the bearing for receiving the derived lubricating oil and contacting the cam and the cam. A cam oil supply device for an engine, comprising a lubricating oil groove for ejecting lubricating oil toward a contact surface with the engine.